1904.] CIRCULATORY SYSTEM IN THE OPHIDIA. 369 



number. Tliere are, for instance, twenty in (jolaher melanoleucus, 

 which has not, I may remark, a specially long liver. 



The arteria epiploica, the longitudinal artery of the fat-body, is 

 fed fi'om several distinct sources. Arteries arise independently 

 from the aoi'ta, from the spennatic arteries, from the oviducal 

 {arterice uterince in Bronn's ' Tliier- Reich'), from the superior and 

 inferior mesenteric, from the renal and gastric arteries. But I 

 have not found all these origins to coexist in the same species. 



It is clear, from the facts at present known, that the rule 

 among the Ophidia is that each gonad ha,s but a single spermatic 

 artery. The exti'aordinaiy length of the testes in Python spilotes 

 may account for their richer blood-supply. It is noteworthy, 

 moreover, that the artery or arteries generally reach the testes at 

 their posterior extremity. 



On the other hand, the ducts of the gonads, whether male or 

 female, commonly receive their blood-supply from a number of 

 separate branches of the aorta. Exceptionally (as in Tropido- 

 notus fasciatus) both ovary and oviduct niay be supplied by 

 branches of the superior mesenteric, in addition to their own 

 proper arteries. And this is the case with the testes in Python 

 spilotes. 



The rencd arteries appear to vaiy from a single one to each 

 kidney {^Python spilotes) to eight such arteries in Coronella 

 catenifer. The close association of the arterial supply of gonad 

 and kidney in Ophiojjhagus hungarus (see p. 357) is quite ex- 

 ceptional. 



Little attention seems to have been paid to the epigastric artery, 

 which, however, exists and has been chiefly studied by me in 

 Ophiophagus. It is a continuous trunk running from end to end 

 of the body in close association with the anterior abdominal vein, 

 and is fed by the carotid anterioily and the fat-body artery 

 posteriorly. As to the venous system, I may chiefly remark upon 

 the epigastric vein, which I have most particularly studied in 

 Ofhiophagus. It extends along the lower body-wall and sends 

 branches to the shorter lobe of the liver along its whole length. 



The portal system of the doi'sal parietes appears to exist in all 

 Snakes. The trunks which arise from the parietes appear never 

 to issue from the muscular walls exactly in the middle line ; they 

 are always to the right or left of that line, and in this they differ 

 from the intercostal arteries. Thei'e is always, or neai'ly always, 

 a specially large trunk in the immediate neighbourhood of the 

 superior mesenteric artery. It is remarkable that the intercostal 

 veins of the trunk should be connected with the portal systems, 

 while those of the "thorax" and neck open into vertebral veins. 



I am able to confirm and extend Gratiolet's discovery* of a 

 suprarenal portal system, which appears to be universally present. 

 I have given above a number of detailed figures showing the 

 number and position of these veins (pp. 358, 364, &c.) in several 

 Snakes. 



* "Note sur le sj'steme veineux des Eeptiles," Journ. cle I'lnst. xxi. 1853. p. 60. 



Proc, Zool, Soc.— 1904, Yol. I. No. XXIY. 24 



